Perhaps the most difficult task of marine rescue operations is locating the person or persons to be rescued. Ocean waves typically have a height of 3-6 feet. Because most life rafts have vertical heights of less than 36 inches, the life raft and its occupants may not be visible from the sea or from a helicopter for up to 50% of the time. A swimmer in the open ocean is nearly impossible to see unless the searchers are very close to the swimmer. Alpine and desert rescue operations are also very difficult because of reduced visibility, possible injury and/or death due to cold or heat exhaustion, and the lack of moisture. These and other problems greatly reduce the efficiency and successfulness of any search operation and consequently rescue missions under such circumstances are extremely costly, time-consuming and difficult.
One prior art attempt at increasing the visibility of a swimmer, life raft, etc., and thereby enhancing the effectiveness of search missions involves the use of a balloon having a highly visible color and/or radar reflective surfaces secured to the swimmer by tether ropes, filled with a lighter-than-air gas and set aloft. The balloon provides increases visibility and also permits the use of radar in search missions.
Unfortunately, a balloon has several drawbacks. For instance, to carry the balloon aloft, a canister of compressed lighter-than-air gas must be provided for injection into the balloon. The canister must be periodically checked and refilled with gas. The combination of canister and balloon is heavy, cumbersome and difficult to use. Because the gas will seep out of the balloon, over time the balloon gradually loses buoyancy. Unless another canister of compressed gas is available, the balloon may no longer be sent aloft.